Regulation of the expression of endopolygalacturonase gene PGUI in Saccharomyces

Previous work in our laboratory has shown that Saccharomyces bayanus strain SCPP is the only reported yeast expressing the three types of pectolytic e nzymes: pectin esterases, pectin lyases and polygalacturonases. One of thes e enzymes, the endopolygalacturonase (endoPG), hydrolyses plant-specific po lysaccharide pectin. The endoPG encoding gene (PGU1) is also present in Sac charomyces cerevisiae. It has been shown that this endoPG is required for t he development of pseudohyphae. Using genomic DNA, the PGU1-1 and PGU1-2 pr omoters of these strains have been amplified and used to construct gene fus ions with the beta -galactosidase gene. On the basis of beta -galactosidase measurements, me compared the expression of both promoters in different en vironmental conditions in order to identify their modulation. We have shown that the PGU1 gene is upregulated by the presence of the pectin and the pr oduct resulting from endopolygalacturonase activity. Moreover, expression o f the PGU1 is also enhanced under respiratory and filament formation condit ions. Copyright (C) 2001 John Wiley & Sons, Ltd.